The present invention relates to a prosthetic implant attachment system and method for mounting a dental prosthesis such as a single artificial tooth or crown, a partial or full denture, or a bridge on an artificial root implant which has previously been embedded in the jaw bone in place of the natural root.
There are at present a number of different dental implant systems in use. Most systems include an artificial root portion or implant cylinder which is placed into a custom bored hole in the jaw bone. A prosthetic coronal section is attached to the artificial root portion when healing and bone integration of the artificial root portion is complete, and a dental prosthetic appliance such as a crown, denture, partial denture or bridge is attached to the coronal section. The prosthetic coronal section must pass through the connective tissue and overlying mucosa for attachment to the prosthesis. There is no interchangeability between the currently available implant systems, so that once a prosthesis has been mounted on one type of artificial root, any future replacements must use the same implant system to mount on that root. In other words, the prosthetic section of one implant system can be secured only to the artificial root of the same system. Since the average lifetime of a prosthesis is of the order of 10 years, at which time a patient may have moved or be seeing a different dentist, significant problems can arise when a replacement is needed. The dental practitioner must always have several implant systems on hand, since patients may have been fitted with various different types of implants at different times, and will also need the appropriate set of tools for mounting the various systems. This problem is likely to become more acute as the number of individuals fitted with such implant systems increases.
Another problem with existing attachment systems is that of adjusting for undesirable placement angulation of the submerged artificial root. Since the prosthetic coronal section or post normally extends coaxially from the artificial root, and the prosthesis must be mounted on this post, undesirable angulation may make it difficult to align the prosthetic tooth or teeth with the natural tooth line. This is a particular problem with front teeth, since for cosmetic reasons it is desirable that a screw or the like securing a crown or artificial tooth to the post does not exit through a front face of the tooth. Some attempts for adjusting angulation are provided in various existing systems, for example providing the post or prosthetic coronal section with a bendable neck portion, but this results in a weakened area which is liable to break. In other systems fixed angled portions are provided on the post, but this allows one angular adjustment only and thus does not allow easy adjustment or a wide range of angulation adjustment.
Another problem with replacing front teeth with existing implant systems is that the post or prosthetic section securing the artificial tooth or teeth to the implant will often be visible between the base of the tooth and the gum, particularly as the gum recedes naturally with time. This results in an unattractive gap which can be seen when the wearer smiles.